1. Field of the Invention
The present invention relates to enhanced extraction and cleaning of fibrous materials like cotton, kenaf and flax. More specifically, the present invention provides an apparatus and a method for reducing cotton waste by lint cleaners.
2. Description of the Prior Art
Over 80 million bales of cotton are produced annually in the world. These cottons are harvested by hand or mechanically by machines called spindle-harvesters or cotton strippers. Depending upon the harvesting method, these cottons are precleaned through various machines in a cotton-gin processing plant and are dried prior to the fiber being separated from the seed. After the fiber is separated from the seed, it is further cleaned by different types of machines that are typically called lint cleaners. Lint cleaners were developed specifically for removing leaf particles, motes, grass and bark that remain in cotton after seed cleaning, extracting and ginning. They were developed and improved in conjunction with the transition from manual to mechanical harvesting of cotton in the United States during the 1950""s. Virtually all gins in the United States have lint cleaning facilities, and over four-fifths of the gins have two or more stages of lint cleaning.
A thorough description of the cotton ginning process and the various components utilized is described by Anthony, W. S., et al. (Editors), Cotton Ginner""s Handbook, Agricultural Handbook No. 503, USDA: Agricultural Research Service, December 1994, the contents of which are incorporated by reference herein.
From the gin stand, the cotton is conveyed to a lint cleaner for the further removal of foreign matter such as trash, plant parts, leaf particles, motes, grass and bark that may remain in cotton after cleaning, extracting and ginning. The most common lint cleaner in the ginning industry is the controlled-batt saw lint cleaner (SLC), although some SLC""s function without the controlled-bat feature (the controlled-batt feature is not necessary for the invention to work). In the SLC, lint from the gin stand is formed into a batt on a condenser screen drum. The batt is then fed through one or more sets of compression rollers and between a feed roller and a feed plate to deliver a batt of uniform thickness onto a saw cylinder. The saw carries fibers under grid bars. While fibers are on the saw cylinder, they are cleaned of foreign matter by a combination of centrifugal force, scrubbing action between saw cylinder and grid bars, and gravity assisted by an air current. After the cotton has passed through the lint cleaner, the cleaned cotton is compressed into bales which must then be covered to protect them from contamination during transportation or storage.
Although the saw lint cleaner is the most effective cleaning machine in the gin, it is also the most damaging to the fibers. Significant damage to the fibers may occur as they are transferred from the condenser and rollers onto the saw cylinder, and as the fibers are cleaned while on the saw. The saw cylinder rotates at a high speed and in the controlled-batt SLC, in a direction which is opposite to the flow of cotton from the roller and feed plate. The abrupt change in speed and direction of the flow of the cotton batt as it is engaged by the saw cylinder creates a combing action, which aligns the fibers and gives them a smoother appearance. However, this also subjects the fibers to a high degree of stress, resulting in fiber breakage. Additional fiber loss and fiber damage occurs as the fibers are carried by the saw cylinder across succession grid bars in all types of SLC""s.
The most common lint cleaner in the ginning industry is called the saw-type lint cleaner which removes 15 to 30 pounds of material per bale, with much of this being useable fiber. In terms of principals of operation, a thin batt of cotton fiber is fed mechanically into a cylinder wound with fine-tooth saws. The saw grasps the cotton fiber and pulls it between the saw cylinder and a set of closely spaced (0.06 to 0.12 inches) cleaning points commonly called grid bars. Saw-type lint cleaners typically have 5 to 9 grid bars each. Each grid bar location creates a cleaning point that separates and ejects cotton fiber and foreign matter from the saw tooth-engaged cotton. The first grid bar separates and ejects a high percentage of foreign matter and a low percentage of cotton fiber. The percentage of foreign matter separated and ejected decreases dramatically and the percentage of cotton fiber separated and ejected increases dramatically as the number of grid bars increase. For example in a 5-grid bar machine, about 25, 23, 22, 15, and 15% by weight of foreign material is separated and ejected by the first, second, third, forth and fifth grid bars respectively. Therefore, as the saw toothed-engaged cotton fiber progresses successively against and under grid bars, decreasing amounts of foreign fiber and increasing amounts of cotton fiber are removed concomitant with an increase in damage to the saw toothed-engaged cotton. Furthermore, cotton fiber is separated from the saw toothed-engaged cotton and ejected, even if no foreign matter is present. Thus, the cost in lost or damaged fiber is substantial.
U.S. Pat. No. 5,909,786 (Anthony) teaches alternate technology for the reduction of fiber waste by lint cleaners by use of shroud members that may be placed on the grids bars of a saw to render individual grid bars inactive. U.S. Pat. No. 5,909,786 teaches the incorporation of shrouds that may be placed in conjunction with individual grid bars to, in essence, inactivate them.
The referenced patent application 09/962,568 hereby incorporated by reference discloses, as part of a larger system to separate contaminants from cotton and flax, an embodiment that utilizes two saw cylinders operating in tandem off of the same doffing brush.
While numerous systems for the cleaning of cotton fibers have been developed, there is clearly a need for an apparatus and method for reducing loss and waste of fiber as it is being processed through a lint cleaner. There is also a need for an enhanced cleaning and separation procol for fibers from other sources, such as kenaf and flax.
Two general types of flax (Linum usitatissimum L.) are grown, one for production of flax fiber and the other for flax seed. The fiber is extracted from fiber flax stalks, and is typically used in the manufacture of linen apparel. The stalk consists of fiber bundles located between the bark surface and an inner wood core (shive), and processes for the separation of the fibers are difficult and expensive. The processes for the separation of fiber from fiber flax normally require that the flax be biologically degraded or retted prior to fiber recovery. In contrast to fiber flax, the seed flax remaining after the seed is harvested is usually considered a waste product. Although the flax in the seed flax stalk is capable of being separated, it is presently considered a waste product because the processes used to separate fiber flax are not feasible with seed flax stalks.
Kenaf (Hibiscus cannabinus L.) is a relative to cotton and okra and grows from eight to twenty feet in height. It represents a good source of fiber and may be utilized in many industries for the production of pulp, paper and paperboard products. Its value in the production of paper is well recognized. The potential economic returns from growth of kenaf are expected to be comparable to that achieved from white corn, milo, and Upland cotton.
Thus, despite the improvements in ginning technology, the need persists for an improved ginning system which will effectively clean cotton while reducing fiber loss. Moreover, there is a need for an improved system for recovering other fiber such as kenaf and flax fiber from straw.
Examples in the instant application are drawn to cotton for which the bulk of the natural plant fiber market exits, but the invention will work with other crops for the purpose of fiber separation.
The present invention accomplishes its desired objects by broadly providing an apparatus (e.g., a saw lint cleaner) for cleaning the fiber. The apparatus includes a frame, two cylinder members (e.g., saw cylinders) rotatably supported by the frame having a cylindrical surface supporting a fiber-engaging structure (e.g., toothed wire or saw teeth), a doffing brush cylinder and a motor coupled to the cylinder member. A grid bar assembly is connected to the frame for assisting in the removal of undesirable particulates from the fiber engaged to the fiber-engaging structure of the cylinder member. The grid assembly comprises a plurality of grid bars connected to the frame in a spatial relationship such that any two grid bars are separated by a grid space. The saw cylinders are so arranged so that they are doffed by the same brush cylinder.
The result of this arrangement is that the material removed by the first saw cylinder which comprises a major proportion of fiber is then put through a second saw cylinder that then recovers the majority of fiber lost in the first saw cylinder. The fiber recovered by the second saw cylinder is then doffed by the same brush that doffs the first saw cylinder. The present invention also accomplishes its desired objects by further broadly providing a method of controlling and/or reducing the loss of fiber during lint cleaning of contaminated cotton.
The method comprises the steps of: providing a lint cleaner that possesses two saw cleaners operating in tandem with the same brush cylinder, such that the waste material removed by the first saw cleaner is then conveyed to the second saw cleaner, which then reseparates the waste and pulls off fiber which is then doffed by the brush cylinder.
It is therefore an object of the present invention to provide an apparatus for fiber cleaning, such as cotton, flax and kenaf.
It is another object of the present invention to provide a method for controlling and/or reducing the loss of fiber during the lint cleaning of contaminated fiber.